Surface coatings on a substrate can comprise multiple coating layers, such as one or more primer layers, one or more color coat layers, and one or more clearcoat layers. An initial coating layer is usually a primer layer for providing adhesion to the substrate and protection. The color coat layers are typically applied over the primer layers for further protection and for providing desired color and appearance effects. Typically, the primer layers are formed from one or more coating compositions having corrosion inhibiting compound and pigments. The color coat layers are formed from one or more color coating compositions that utilize one or more pigments or effect pigments to impart the desired color or appearance, such as solid, metallic, pearlescent effect, gloss, or distinctness of image, to the substrate, such as a vehicle body. Metallic flakes, such as aluminum flakes are commonly used to produce coatings having flake appearances, texture, sparkle, glint and glitter as well as the enhancement of depth perception in the coatings imparted by the flakes. In certain instances, a unilayer coating (“unicoat”) can be applied over the substrate which contains the corrosion inhibiting compound and any optional coloring pigments. The clearcoat layers can be formed from one or more clearcoat compositions for providing further protection and desired appearance, such as mar and scratch resistance, high gloss and distinctness of image.
The surface coatings are typically formed by sequentially applying selected coating compositions for the desired coating layers and cure or dry the coating layers sequentially or simultaneously.
Currently, characteristics of the color coat, color coat layers are typically measured after the one or more clearcoat layers are applied and formed over the color coat layers that are already formed.